applications: nrf5340_audio: nRF5340DK LED and button support

Support for LED state indications and button controls on the nRF5340 DK.

NOTE: For headsets there is still no audio output hardware codec

Signed-off-by: Graham Wacey <[email protected]>

Author: gWacey

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -205,14 +205,18 @@ Matter bridge
 
 nRF5340 Audio
 -------------
+
+* Added:
+
+  * Experimental support for Audio on the nRF5340 DK, with LED state indications and button controls.
+
 * Updated:
 
   * The application to use the ``NFC.TAGHEADER0`` value from FICR as the broadcast ID instead of using a random ID.
   * The application to change from Newlib to Picolib to align with |NCS| and Zephyr.
   * The application to use an audio struct that contains meta data about the audio stream.
   * The optional buildprog tool to use `nRF Util`_ instead of nrfjprog that has been deprecated.
 
-
 nRF Desktop
 -----------